Methods of making phthalocyanine pigments



Patented May is, 1945 UNITED STATES PATENT OFFICE METHODS OF MAKINGPHTHALOCYANINE;

' PIGMENTS Vito A. Giambalvo, Rahway, N. J assignor to InterchemicalCorporation, New York, N. Y., a

corporation of Ohio No Drawing. Application September 23, 1942,

Serial No. 459,439

B Claims. (Cl. 260314.5)

This invention relates to the production of the blue to green pigmentsof the copper phthalocyanine class, and aims to provide a simple, in-

expensive method of preparing such pigments characterized by low costand easeof operation. Copper phthalocyanine blue is conventionallyprepared from copper, phthalic anhydride and ammonia as the basic rawmaterials; the green is prepared by substituting chlorine in the benzenenucleus. The blue was first prepared by de Diesbach and Von der Wied(Helvetica Chemica Acta 10-1927-p. 886 et seq.) from phthalonitrile anda copper salt in pyridine, and from o-brom benzene and copper cyanideunder pressure; the first commercial attempts to produce the productappear to have been made byreacting phthalic anhydride or phthalimide,ammonia gas and metal (Dandridge et' al.-British Patent No. 322,169).Because of the low yields obtained (of the order of to the art soon wentover to a two-stage process, in which phthalonitrile was first obtainedfrom phthalic anhydride and amsults' with small amounts of cyanuricacid, asv

. compared with the reaction in its absence; but

the yields increase in a comparatively linear f ashion until enoughcyanuric acid is present to thee retically produce the metal salt. Fromthen on,

further additions of cyanuric acid do not produce any increase in yield.

The reaction may be carried out in the presence or absence of inertdiluents to dampen the exothermic reaction. Excess phthalimide is a verysatisfactory diluent, but other carriers, such as urea, naphthalene andsodium sulfate, maybe used. Known catalysts may likewise be added.

The following are typical examples of my invention:

, Example 1 14.7 grams of phthalimide, 13.0 grams'of cyanuric acid and4.7 grams of cupric chloride di-.

hydrate are thoroughly dry mixed and heated with good agitation at225-230 C. for one hour.

The reaction product is cooled, pulverized and monia by progressivedehydration, and the;

phthalonitrile was then reacted with a metallic compound. The costinvolved in separating and purifying the nitrile, howeven kept' interestalive in a one-stage process. Such a process was made commerciallyfeasible by conducting the reaction between phthalic anhydride, ammoniaand copper in molten urea; yields of the order of of theory are obtainedin this fashion. The yields obtainable by this method have been furtherimproved by the use of catalysts.

I have discoveredthat copper and similar metallic phthalocyanine bluesand greens may be prepared directly from phthalic anhydride (or otherstarting materials capable of producingan ortho-arylene 'dinitrile bydehydration and reaction with ammonia), ammonia, and the copper or othermetal) salt of cyanuric acid in a simple;

leached with 400 cc. of 5% boiling NaOH. The exces phthalimide andcyanuric acid are recoverable from the leach liquid. The dry leachedblue is dissolved in 10 parts of concentrated sulfuric acid, and thendrowned in 100 parts of boiling water, filtered, washed and dried.

' bluish pink precipitate is filtered, washed and Yield 'lb grams ofcopper phthalocyanine =52.8% of theory.

Ezcample 2 13.0 grams of C. P. cyanuric acid are dissolved in 1000 cc,of 2.0% ammonium hydroxide, and copper ammonium sulfate is added toexcess. The

dried. The copper ammonium cyanurate thus formed is dry mixed with 14.7grams of phthalimide and a trace of cupric chloride. The dry mixture isheated at 225-230 C. for one hour on a sand bath. The reaction productis cooled, pulverized and leached with boiling NaOH. The dry leachedblue is dissolved in 10 parts of concentrated I-IzSOi and then drownedin 100 parts of boiling water, filtered, washed and dried.

Yield-8.5 grams =59.0% of theory.

Example 3 14.8 pounds of phthalic anhydride, 13.0 pounds of cyanuricacid, and 4;.7 pounds of cupric chlowith ammonia, and thus can-be used.For the green pigments, the proper nuclear substituted equivalents areemployed.

The copper or other metal can be added inany I form which will reactwith cyanuric'acid, provided sufficient cyanuric acid is present to formthe metal cyanurate. I have observed improved reride dihydrate arethoroughly dry mixed and heated with good agitation to 200 C. Dryammonia is passed through the reaction mass, and

the temperature allowed to rise to 250 C. where it is kept for onehour.

The reaction mass. is then worked up as in Example 1.

Yield-7.5 pounds.

=52.8% of theory."

2 2,375,780 Examples obviously can be multiplied indefinitely withoutdeparting from the scope of the invention; as defined in the claims. Inparticular,

' phthalicanhydride and phthalimide can bereplaced by equivalentcompounds, as outlined above; and copper can be replaced by metals; suchas iron, cobalt, nickel, etc, which produce similar metallic products.Furthermore, nuclear substituted products, such as the greens obtainedfrom the chlor-substituted phthalic anhydride, 1

can be produced by my method.

I claim: Y

1.. The method of producing a metallic phthalocyanine which comprisesreacting by heat cyanuric acid and a metallic compound reactable 15therewith with a compound capable of producing an aromaticortho-dinitrile by dehydration and reaction with ammonia.

2. The method of producing a metallic phthalocyanine in high yield whichcomprises reacting 20 by heat a metal cyanurate with a compound capableof producing an aromatic ortho-dinitrile by dehydration and reactionwith ammonia.

3. The method of producing copper phthalocyanine in high yield whichcomprises reacting by heat copper cyanurate with a compound capable ofproducing an aromatic ortho-dinitrile by dehydration and reaction withammonia.-

4. The method of producing copper phthalocyanine which comprisesheat-reacting copper cyanurate with phthalimid.

5. The method of producing copper phthaloacting with cyanuric acid, andsufiicient cyanuric acid to substantially convert all thecopper compoundto copper cyanurate.

VITO A. GIALEALVQ.

